EP2341960A1

EP2341960A1 - Needle-less, disposable injector provided with high injection safety

Info

Publication number: EP2341960A1
Application number: EP09778024A
Authority: EP
Inventors: Bodo Asmussen; Hans-Rainer Hoffmann
Original assignee: LTS Lohmann Therapie Systeme AG
Current assignee: LTS Lohmann Therapie Systeme AG
Priority date: 2008-09-23
Filing date: 2009-08-21
Publication date: 2011-07-13
Anticipated expiration: 2029-08-21
Also published as: ZA201101578B; CN102159266A; BRPI0919139A2; EP2341960B1; AR073306A1; IL211724A0; RU2534406C2; DE102008048595A1; AU2009296618A1; RU2011110769A; CA2735696A1; US8287490B2; MX2011003065A; WO2010034380A1; JP2012502707A; US20110208119A1; JP5520303B2; KR20110063770A; KR101535700B1; RU2534406C9

Abstract

The invention relates to a needle-less, disposable injector comprising a housing (10), which has at least one compression bar, a cylinder-piston unit (100), a plunger-actuating ram (60), a trigger unit (80) and a spring energy reservoir (50), wherein the trigger unit locks the pretensioned spring energy reservoir by means of the compression bar. During triggering, the compression bar slides along at least one trigger element (82) of the trigger unit and, after triggering the trigger unit, the spring energy reservoir displaces the compression bar by means of the plunger-actuating ram and actuates the cylinder-piston unit. When loaded by the pretensioned spring energy reservoir, the pairing formed by the mutually facing inner wall of the trigger element and the contact surface of the compression bar has at least in areas a higher sliding friction coefficient than the pairing formed by the mutually facing collar surface of the plunger-actuating ram and the support surface of the compression bar. The present invention provides a disposable injector where the required minimum contact-pressure force is ensured during use thereof.

Description

NADELLOSER E INWEG INJECTOR WITH HIGH INJECTION SAFETY

Description:

The invention relates to a disposable injector having a housing which comprises at least one pressure rod, with a cylinder-piston unit, with a piston actuation plunger, with a trip unit and with a spring energy storage, wherein the trip unit first locks the prestressed spring energy storage means by means of the pressure rod when triggering the push rod on at least one trigger element of the trip unit slides along and wherein displaced after triggering the trip unit of the spring energy storage means of the piston actuating punch the pressure rod and actuates the cylinder-piston unit.

From the post-published DE 10 2007 034 871 such a disposable injector is known. If this injector is exposed to the injection site with too little pressure, there is a risk that injection solution will escape in a lateral direction to the axis of the injection jet. It comes to a so-called wet-shot.

The present invention is therefore based on the problem to develop a disposable injector, in its use, the required Mindestanpresskraft is ensured. This problem is solved with the features of the main claim. For this purpose, when loaded by the prestressed spring energy storage, the pairing of the mutually facing inner wall of the trigger element and the contact surface of the pressure rod at least partially a higher coefficient of sliding friction than the pairing of the mutually facing collar surface of the Koben benbetätigungsstempels and the support surface of the push rod.

Further details of the invention will become apparent from the dependent claims and the following descriptions schematically illustrated embodiments.

Figure 1: disposable injector with two deformed in locking position pressure bars;

FIG. 2: disposable injector when triggered; FIG. 3: disposable injector after release;

FIG. 4: detail from FIG. 1;

FIG. 5: section through FIG. 4;

FIG. 6: top view of the development of a contact surface;

FIG. 7: Variant to FIG. 5; FIG. 8: a view of the development of an inner wall;

FIG. 9: Variant to FIG. 8.

Figures 1 to 3 show a disposable injector in three different triggering states. In the figure 1 the disposable injector is shown prior to filling and triggering. FIG. 2 shows the disposable injector upon release and FIG. 3 after release. The one-way injector shown in Figures 1 - 3 consists of a housing (10), a cylinder-piston unit (100), a piston actuating plunger (60) and a helical compression spring (50) as a spring energy storage. In addition, a triggering unit (80) with a triggering element (82) and a securing element (90) are arranged on the housing (10). The cylinder-piston unit (100) is closed in front in the illustration of Figure 1 by means of a closure cap (120) in combination with a plug (128).

The housing (10) is a one-piece, cup-shaped, open-bottom hollow body with overhead floor (39). It is e.g. made of a glass fiber reinforced polyamide by injection molding. The housing (10) has a substantially tubular shape and is divided into two functional areas, which is on the one hand, the upper cladding region (31) and on the other hand, the lower fixing region (41).

In the jacket area (31), the housing (10) has e.g. two opposing window-like openings (33). At the lower edge of the single opening (33) in each case a pressure rod (21) is formed as an elastic bending beam. The point of application for the printing bars (21) is just above the fixing area (41). To form the respective pressure rod (21) is in the lower region of the jacket portion (31) has a narrow, at least approximately U-shaped gap surrounding the individual pressure rod (21) laterally and above.

The pressure rod (21) has, for example, 80% of its length, the wall thickness and the curvature of the wall of the housing (10). Among other things, this area also has the function of a spring-elastic bending beam (28). He has a crescent-shaped cross-section. Possibly. a part of this bending beam (28) may also be provided with a rectangular cross section in order to reduce bending stresses occurring in use in the bending beam edge area.

In injectors in which the piston actuating ram (60) in the housing (10) - at least partially - is straight with little clearance and the piston actuating ram (60) has sufficient bending strength, instead of two or more pressure rods (21) and only a single push rod ( 21) can be used.

The upper free end of the individual pressure rod (21) is formed by the radially outwardly projecting cam (22). The latter has at least one support surface (23) oriented in the direction of the center line (5) and a contact surface (24) facing away from the center line (5).

In the lower region of the housing (10) are holding elements for fastening the cylinder-piston unit (100). In the exemplary embodiment, the cylinder-piston unit (100) consists of a transparent cylinder (101) which can be filled with an injection solution (1). In the illustration of Figure 1 sits a piston (111) in the forward position. Above the piston (111), in the housing (10), the piston-actuating ram (60) is e.g. arranged so that it does not touch the piston (111), but with its lower end, e.g. is guided laterally in the upper region of the cylinder (101).

The lower half of the housing (10) is of the sleeve-like

Surrounding trigger element (82). This is, for example, substantially cylindrical and made, for example, of acrylonitrile-butadiene-styrene copolymer (ABS). The triggering element (82) is longitudinally mounted on the radially outer surface (13) of the housing (10). slidably mounted. It ends at the rear with a sharp edge (85), which is part of a front-side return edge (84) of the trigger element (82). Below the edge (85), according to FIG. 1, cams (22) formed on the pressure rods (21) touch the inner wall (59) of the trigger element (82) with their outer contact surfaces (24).

For example, in the vicinity of the edge (85) on the trigger element (82) a trigger cap (81) is fixed, which completely surrounds the rear end of the housing (10). The trigger cap (81) comprises a circumferential widening (83), in which the cams (22) are received when the injector is triggered, cf. FIG. 3. Instead of this widening (83), in the case of a non-rotationally symmetrical triggering element (82), there may also be partial widenings or uncovered openings per push rod (21). Above the widening (83), the trigger cap (81) slidably abuts the outer wall (13) of the housing (10).

At the front end of the trigger element (82) closes the cap (120). The latter encloses the lower part of the cylinder-piston unit (100). The closure cap (120) has an adapter opening (127) at the front end side with e.g. a Luer inner cone, which is closed sterile by means of a außenkegligen plug (128). The closure cap (120) is mounted here on the lower region of the housing (10).

The in the housing (10) arranged piston actuating ram (60) is divided into two areas. The lower area is the spool (76). Its diameter is slightly smaller than the inner diameter of the rear portion of the cylinder (101). The lower end face of the spool (76) acts directly on the piston (111). The upper area of the piston-actuating punch (60), the punch plate (73), is a flat, at least partially cylindrical disk whose outside diameter is a few tenths of a millimeter smaller than the inside diameter of the housing (10) in the collar area (31). The lower end face has a collar surface (75) arranged around the piston slide (76). It has the shape of a truncated cone whose tip angle is about 100 to 140 degrees. In the illustrated embodiment, the collar surface (75) has a point angle of 140 degrees. The imaginary tip of the truncated cone jacket lies on the center line (5) in the region of the piston slide (76). The collar surface (75) may also be spherically curved.

Of course, the piston slide (76) can also be designed as a separate component, separate from the stamp plate (73). For this purpose, it is then guided on the inner wall of the housing (10).

Between the stamp plate (73) and the uppermost bottom (39) of the housing (10), the helical compression spring (50) is prestressed. The helical compression spring (50) is supported on the upper floor (39) of the housing (10) with the interposition of a spacer sleeve (19). The spring force of the helical compression spring (50) is transmitted to the pressure rods (21) via the punch plate (73). Due to the inclination of the collar surface (75), the pressure rods (21) are urged radially outwardly in the manner of a wedge gear. The release sleeve (82) supports this radial force permanently.

The piston actuating punch (60) has a guide pin (62) above the punch plate (73). The latter guides or is guided by the helical compression spring (50). Below the stamping plate (73) is centrally in the extension of the guide pin (62) of the spool (76), which in a Actuation of the disposable injector on the piston (111) acts. The piston slide (76) has a cone-shaped, forward curved end face (77), see. Figure 2. With this end face (77) he contacted when triggering the complementary shaped end face of the piston (111), see. Figure 3. Both cones have at least approximately the same cone angle.

Before the disposable injector is filled and used, the spring energy store (50) is biased, cf. Figure 1. The two pressurized pressure rods (21) hold the piston actuating ram (60) on the stamp plate (73) in its biased position. For this purpose, the pressure rods (21) are supported with their Abstutzflächen (23) on the punch plate (73). The size of the respective contact surface between a support surface (23) and the corresponding location on the stamp plate (73) is in the range of 2 to 20 mm ² . For example, both the support surface (23) and the collar surface (75) facing it, with which it forms a pair, have an average roughness value smaller than ten micrometers. For example, the average roughness is six microns.

The bending elasticity of the pressure rods (21) and the punch plate (73) press the support rods (21) at least approximately radially outward against the trigger element (82). There they are on cam (22) on the trigger element (82). The cams (22) may be e.g. also be 5 to 20 millimeters below the respective free upper end of the pressure bars (21).

According to Figures 1 and 4 is located on the support surface (23) of the stamp plate (73) of the tensioned disposable injector on his

Waistband (75) on. The support surface (23), which in this case fulfills the function of a wedge surface, has the shape of a truncated cone shell with a point angle of 140 degrees. Possibly. have the pressure bars (21) or the collar surface (75) at least in the contact area a ceramic armor. The collar surface (75) can be reinforced by, for example, a glued-on flat washer.

The abutment surface (24) of the cams (22) is part of a cone whose maximum diameter is e.g. 3 to 4 millimeters larger than the outer diameter of the housing (10). The contact surface (24) contacts the inner wall (59) of the sleeve-like triggering element (82) when the disposable injector is tensioned. The contact area is shown enlarged in FIG. Thereafter, the contact surface (24) is pressed against the inner wall (59) of the triggering element (82) due to the bending of the individual pressure rod (21), especially in its lower region. The contact surface (24) can be structured or roughened. For example, it can in a plan view of a settlement of the contact surface (24) arranged in the transverse direction grooves, see. FIG. 6 or a diamond pattern, cf. FIG. 7. For example, these patterns are evenly arranged. The center roughness of the abutment surface (24) is e.g. greater than ten microns.

In the illustration of Figure 7, the width of the contact surface (24) of the individual pressure rod (21) grows from bottom to top. Hereby, the contact pressure of the contact surface (24) on the inner wall (59) in the lower region is higher than in the upper. To enhance this effect, the contact surface (24) in the transverse direction may have a smaller radius than the inner wall (59), cf. FIG. 5. The width of the contact surface can therefore be smaller than the width of the individual pressure rod (21).

In order to use the disposable injector, first the cylinder-piston unit (100) must be filled. For this purpose, the plug (128) is removed from the adapter opening (127) and an injector tion solution (1), for example, pressed or sucked. The piston (111) is in this case pushed back or withdrawn.

To unlock the injector, the securing element (90), e.g. pulled off a tear strip (94), so that the adhesive bond between the cap (120) and the trigger element (82) is released. The cap (120) is removed. The disposable injector is positioned on the injection site. The spring energy store (50) is tensioned, and the push rods (21) continue to support the collar surface (75) of the punch plate (73).

Now the trigger element (82) in the direction of the cylinder-piston unit (100) can be moved, see. FIG. 2. The state shown in FIG. 2 is not static and will therefore be referred to below as a fictitious state.

When the disposable injector is triggered, the trigger element (82) slides linearly downwards on the outer wall (13) of the housing (10) in the release movement direction (6), ie in the direction of the injection site. The contact surfaces (24) of the pressure rods (21) slip over the edge (85). The pressure rods (21) bend elastically outwards into their actual starting position and jump under the force of the spring element (50) radially outward into the widening (83).

The widening (83) is exactly positioned and dimensioned with respect to the housing (10) in such a way that it can receive the outwardly compressed pressure rods (21) with their cams (22) that recede during the release process. The inner contour of the widening (83) is, for example, a channel with a return flank (84), which here represents a plane normal to the center line (5) of the injector. Once the cams (22) are displaced in the expansion, the piston actuating punch (60) jumps freely down, cf. Figure 3. The piston (111) is pressed down. The cylinder (100) is emptied.

The inner wall (59) of the trigger element (82) is the area, on which the contact surface (24) slides along, for example roughened or structured. The roughness values correspond e.g. the roughness values of the contact surface (24). In one structure, the pattern may be formed as shown in FIGS. 6 or 7.

The structural density and / or the roughness of the inner wall (59) can also increase with the stroke of the relative movement of the contact surface (24) to the inner wall (59) of the trigger element (82). For example, in FIG. 8, a structure pattern adjacent to the sharp-edged edge (85) is shown with parallel grooves, the spacing of which decreases from bottom to top. FIG. 9 shows a scale pattern whose scales can be positive and / or negative. The distance of the scales decreases in the direction of the relative movement - from bottom to top - from. The lowermost region of the contact surface of the inner wall (59) against which the abutment surface (24) abuts before being triggered is structurally free, for example.

Before triggering and when the disposable injector is triggered, the coil spring (50) presses the cams (22) outward via the stamp plate (73). Due to the low coefficient of sliding friction, which results from the large contact surface and the low surface roughness of the mating of the collar surface (75) and the support surface (23), this wedge gear has a high efficiency.

In order to trigger the disposable injector after it has been placed on the injection site, the operator must first of all determine the stiction between the contact point caused by the contact pressure force, for example. Overlay the bearing surface (24) and the inner wall (59). This stiction is higher, the smaller the contact surface of the mating and the higher the surface roughness.

The user will therefore press the disposable injector against the injection site all the more, the higher the static friction force. In the static state, therefore, a high roughness value of the pairing of the contact surface (24) and the inner wall (59) ensures that the user continues to press the disposable injector against the injection site with a minimum force after placement.

As soon as the user has overcome the static friction force when triggered, the inner wall (59) of the triggering element (82) slides along the contact surfaces (24). The sliding friction coefficient of the pairing of these two surfaces (24, 59) depends on the materials involved, the surface roughness and / or the surface structure and the surface pressure. The sliding friction coefficient of this pairing is greater than the sliding friction coefficient of the pairing formed by the collar surface (75) and the support surface (23). If, for example, the contact surface (24) and the inner wall (59) are designed with a structure according to FIG. to move the trigger element (82) requires an approximately constant high feed force. The user will thus continue to press the disposable injector with a force against the injection site that is equal to or higher than the injection force required for a safe injection.

The user must apply this force until the trailing edge (25) has reached the edge (85). Owing to the low sliding friction of the pairing formed by the collar surface (75) and the support surface (23) and the small wedge angle, the cams (22) are abruptly displaced into the widenings (83). When a disposable injector is triggered, whose inner wall (59) has, for example, a structure according to FIG. 8, the force required for triggering increases during the displacement of the triggering element (82). The user is thus forced to press the disposable injector increasingly against the injection site. This ensures that when releasing the spring energy, the disposable injector is pressed so forcefully against the injection site that a wet-shot is prevented.

The required feed force of the trigger element (82) to overcome the static friction may be less than the required feed force to overcome the sliding friction. For this purpose, the inner wall (59) may be e.g. be executed as shown in the figure 9. The area of the inner wall (59), in which the abutment surface (24) abuts before being triggered, has here, for example, a low surface roughness. As soon as the contact surface (24) has left this area, the roughness and thus the coefficient of sliding friction increases. For example, the user may be forced to make a steady or linearly increasing

To have to use force to trigger. At least the feed force which must be applied immediately before the cams (22) pop out is greater than or equal to the minimum contact force required for a safe injection.

Optionally, the material of the Kolbenbetätigungsstempels (60), the push rods (21) and the trigger element (82) may be identical.

In the variants shown in the figures, the single contact zone between the pressure rod (21) and the stamping cell (73) is embodied as surfaces (23) and (75) which make sliding contact with one another. In a particular embodiment, in each area (23) of the individual pressure bars (21) a roller can be loaded. Gert, which is roller-mounted on an actuation of the injector on the surface (75) of the stamping plate, that is, friction, unrolls.

Instead of a linear sliding movement of the trigger element (82) on the housing (10) can also be provided a helical movement. In this case, the trigger element (82) and the housing (10), e.g. led over a sliding block and a backdrop to each other. Possibly. the release can also be realized by a pure pivoting movement between the housing (10) and the trigger element (82). The pivot axis would be here the center line (5).

Of course, it is also conceivable to combine the various embodiments with one another.

List of reference numbers:

1 solution for injection; drug

5 Injector Centerline, Longitudinal 6 Tripping Direction of Movement (82), Downward Directional Arrow

10 housings, one-piece

13 outer surface, cylindrical 19 spacer sleeve

21 pressure rods, support rods; Hitch

22 cams

23 support surface 24 contact surface

25 trailing edge

28 bending beams

31 Sheath area 33 breakthroughs

39 floor

41 Fixing area for the cylinder-piston unit

50 spring element, helical compression spring, spring energy storage

59 inner wall of (82)

60 piston actuating punch 62 guide pin

63 bore, through hole

73 stamp plates

75 waistband, conical 76 piston valve

77 Piston end face, cone-shaped

80 Tripping unit 81 Tripping cap

82 triggering element

83 expansion

84 return edge

85 edge, sharp-edged

90 tamper-evident closure, band, securing element

94 tear-off band

100 cylinder-piston unit 101 cylinder

111 pistons

120 Cap, adhesive seal 127 Adapter opening

128 plugs

Claims

Claims:

1. disposable injector comprising a housing (10) comprising at least one pressure rod (21), with a cylinder-piston unit (100), with a piston actuation plunger (60), with a trip unit (80) and with a spring energy storage (50) , wherein the trip unit (80) first locks the prestressed spring energy accumulator (50) by means of the pressure rod (21), wherein upon release the pressure rod (21) slides along at least one trigger element (82) of the tripping unit (80) and whereby after Triggering the trip unit (80) of the spring energy storage (50) by means of the piston actuating punch (60) the pressure rod (21) displaced and the cylinder-piston unit (100) actuated, characterized in that when loaded by the prestressed spring energy storage (50) the pairing the mutually facing inner wall (59) of the trigger element (82) and the contact surface (24) of the pressure rod (21) at least partially has a higher Gleitreibungs- coefficient as the pairing of the facing collar surface (75) of the piston actuating punch (60) and the support surface (23) of the push rod (21).

2. disposable injector according to claim 1, characterized in that the triggering element (82) engages around the housing (10) at least in sections like a sleeve.

3. disposable injector according to claim 1, characterized in that it comprises two pressure rods (21).

4. disposable injector according to claim 1, characterized in that the average roughness of the contact surface (24) and / or the inner wall (59) at least in the contact region of these surfaces (24, 59) is greater than or equal to ten microns.

5. disposable injector according to claim 1, characterized in that the roughness of the inner wall of the triggering element (82) in the direction of a sharp-edged edge (85) increases.

6. disposable injector according to claim 1, characterized in that the width of the used contact surface (24) is smaller than the width of the individual pressure rod (21).